Isro’s redesigned cryogenic engine faces test in January

The advantage with the revamped cryogenic engine is that all different parts of the engine can be addressed separately, says Isro chairman K. Radhakrishnan. Photo: Aniruddha Chowdhury/Mint

Updated: Tue, Apr 09 2013. 11 42 PM IST

New Delhi: The Indian Space Research Organisation (Isro) plans to redesign its cryogenic engine—a critical component of its future, heavy-duty space vehicles—that, while less powerful for its weight, will allow the space agency to develop more economical engines and reduce the cost of satellite launches by a third.

Isro’s continuing struggle to develop a reliable cryogenic engine is a major stumbling block in realising its ambition to launch heavier satellites or put a man in space.

In January, the space agency will test the new engine on a rocket that will not seek to place a payload in orbit.

The rocket will be the GSLV-III, the newest variant of the Geosynchronous Satellite Launch Vehicle that are all of Russian make and can launch satellites no heavier than 2.2 tonnes.

The last time Isro tested its cryogenic engines was in 2010, when it faced two failures. All the previous engines it has used are based on Russian technology and though the agency will test another indigenous cryogenic engine this July, it will be very similar in design to existing Russian designs.

The cryogenic engine is the last of the multiple stages of a rocket that ignites and is the final propeller of a satellite into a designated orbit. It generally consists of extremely cold fuel —liquid oxygen and hydrogen—and is considered to be among the trickiest bits of the space vehicle’s journey.

“This engine will have a slightly reduced specific impulse (a variable that shows the amount of thrust that can be generated for the weight an engine carries),” said K. Radhakrishnan, chairman, Isro. “However, the advantage is that all different parts of the engine can be addressed separately,” he added, referring to the engine to be tested in January.

A senior official who’s in charge of the GSLV-III project said that because the new design is so different from what has been previously attempted, there will be many different measurements that need to be computed, and that the actual firing of the cryogenic stage becomes relatively unimportant.

“The aerodynamical challenges of this design will be radically different and so we are measuring nearly 2,000 different parameters,” said S. Somnath, project director GSLV. “After this GSLV goes 120 kilometres above (ground), it will fall back into the sea and won’t enter orbit.”

The test flight in January will be an experimental flight, said Somnath, and it will be followed by two other tests or so-called developmental flights later in the year.

Between 2013 and 2014, Isro has planned 16 missions—the highest ever in the space of two years—but all of them involve light satellites and several analysts say that to capture a bigger share of the satellite launch market, Isro must graduate to launching heavier satellites that weigh at least four tonnes.

“The future of space agencies is commercially driven,” said Alok Mishra, a defence and strategic studies analyst. “Commercial space vehicles are ferrying humans, which requires at least 30-tonne payloads and all major satellite launches are now over five tonnes.”